Ameroseiella Bregetova, 1977

Masan, Peter, 2017, A revision of the family Ameroseiidae (Acari, Mesostigmata), with some data on Slovak fauna, ZooKeys 704, pp. 1-228 : 1

Genus Ameroseiella Bregetova, 1977

Ameroseiella Bregetova, 1977: 167. Type species: Ameroseius apodius Karg, 1971 (= Ameroseius macrochelae Westerboer, 1963; new synonymy), by original designation.

Diagnosis (adults).

Dorsal shield well sclerotised and coarsely ornamented, with 29 pairs of setae, including z6, similar in length and form, thickened, often flattened, with longitudinal vein and smooth or sparsely serrate lateral margins; setae j1 differently formed, leaf-like to fan-shaped, with distinctive longitudinal midrib and regularly denticulate anterolateral margin. In female, sternal setae on sternal shield (st1, st2), soft integument (st3, st4) and epigynal shield (st5); opisthogastric region with six pairs of setae (JV1-JV5, ZV2), all on soft integument (anal shield with only three circum-anal setae). In male, ventrianal shield with 3-4 pairs of opisthogastric setae (JV1 on or off the shield, JV5 always off the shield); setae JV4 absent. Opisthogastric setae mostly smooth, short and needle-like; setae JV4 pilose; setae JV5 modified and similar to those on dorsal shield. Corniculi normally sclerotised, relatively slender, with splitted apex; setae h1 markedly thickened. Cheliceral digits relatively large, fixed digit of chelicera with three well developed teeth on proximal masticatory area (two proximal teeth somewhat adjacent). Epistome with anterior margin produced into long and narrow central projection. Palptarsal apotele two-tined. Genu III, and tibiae III-IV with two anterolateral and two posterolateral setae. Tarsi of legs I with empodium and claws not developed, terminating with four conspicuously lengthened sensory setae and some shorter ones; tarsi II-IV each with normal empodium and claws.

Remarks.

The genus Ameroseiella Bregetova, 1977 was originally diagnosed from other ameroseiid genera by the absence of pretarsal empodium and claws on legs I. This genus was considered as a synonym of Ameroseius Berlese, 1904 ( Karg 1993, 2005). In the meantime, Evans and Till (1979) and Halliday (1997) accepted Ameroseiella as a distinct genus, and their concept is adopted in the present paper because the genus exhibits some character states presented by Kleemannia and others by Ameroseius . For example, the presence of anal shield and three teeth on fixed cheliceral digit is not consistent with Kleemannia , whereas the presence of two posterolateral setae on genu III and tibiae III-IV, pointed epistome, thickened h1 are the features not consistent with those found in Ameroseius .

The concept of Ameroseiella is based especially on the following combination of characters: (1) leg I without ambulacrum and terminating in lengthened setae; (2) dorsal shield with 29 pairs of setae; (3) setae j1 fan-shaped and with longitudinal midrib; (4) in female, st3 on soft integument; (5) in female, anal shield only with three circum-anal setae; (6) setae JV5 similar to those on dorsum; (7) cheliceral digits robust, fixed digit with three large teeth; (8) epistome with pointed medial process; (9) setae h1 thickened; (10) palptarsal apotele two-tined.

Ameroseiella is distributed exclusively throughout the Palaearctic region, and it currently comprises two species reported from Europe and Asia. They occur in various decomposing organic materials like compost and dung, and in the nests of mammals and birds ( Westerboer and Bernhard 1963, Karg 1971a, Bregetova 1977).

Key to species of Ameroseiella occurring in Europe (adults)

1	Dorsocentral setae relatively narrow, with lateral margins parallel and sparsely serrate; postanal seta thickened, densely pilose, almost brush-shaped	Ameroseiella macrochelae (Westerboer, 1963) (Plates 1 , 2 )
-	Dorsocentral setae flattened, foliately expanded in medial portion, with smooth lateral margins; postanal seta thin, smooth and needle-shaped	Ameroseiella stepposa Bregetova, 1977

Figures

Plate 1. Ameroseiella macrochelae, female, dorsal idiosoma.

Plate 2. Ameroseiella macrochelae, female. A Dorsal idiosoma with proximal leg segments B Tarsus I, distal part C Setae j 1 and epistome D Anal shield E Chelicerae, distal parts, dorsal view.